An electrical outlet box provides a termination point for wires carrying electrical current through buildings, houses and other structures. Wiring entering an outlet box is typically connected to a particular electrical fixture or receptacle such as a plug outlet or switch. The receptacle is mounted within the box along with a portion of the wiring connected to the receptacle. The box is then typically covered by a face plate having an opening therein to allow access to the outlet or switch while preventing electrified components from being exposed. Outlet boxes may be employed in concealed-wiring installations in which they are located within a wall or ceiling. Alternatively, outlet boxes may be used in exposed-conduit wiring installations where they are exteriorly mounted to a wall, column or ceiling.
Outlet boxes are available in a variety of configurations and sizes. The selection of which type of box to use is dependant upon the specifics of the application. The most commonly employed box is a single-gang outlet box, also referred to as a standard outlet box. The single-gang box is ideal for applications in which only one receptacle is required for the application. Standard outlet boxes have opening dimensions of approximately 3".times.21/4" and are available in a variety of depths. Double-gang and triple-gang boxes are also available, and they typically have the capacity to hold two and three receptacles respectively. A four inch (4") square box is also commonly employed for multiple receptacle applications.
In order to install the receptacle, an installer is required to pull the wire through openings in the outlet box wall. Outlet boxes typically include such openings in the box wall in order to provide entry for the wires into the box. These openings are usually covered by removable portions called "knockouts" which can be easily removed by the installer as required. The pulling of the wires through the knockout openings, however, can prove fairly difficult and time consuming especially when the wire sizes are relatively large. This task becomes even more difficult when the outlet box does not provide adequate room for the installer to manually reach into the box. Large wires sizes such as AWG #6 to #12 are difficult to bend and manipulate, thereby increasing the time required for installation. Such large wire sizes are typically employed in residential applications for clothes dryer installations as well as cooking range installations. This is due to the fact that such devices typically operate at 240-250 volts and carry relatively large amounts of current, 30-50 Amps. The large wire sizes, therefore, are required to safely meet the load requirements of appliances such as ranges and dryers.
Large wires sizes also present a problem of storage of the wires once the receptacle has been connected. After the wires have been pulled through the wall openings into the box and the receptacle hooked up, a certain length of wire along with the receptacle must be stored in the outlet box. It is beneficial to store a sufficient amount of wire in the outlet box so that upon subsequent removal of the receptacle, the stored wire will unfold allowing for the receptacle to be serviced. If an insufficient amount of wire is stored in the outlet box, the wiring will tend to prevent the receptacle from being fully removed thus making any maintenance procedures time consuming and difficult. Storing an adequate amount of wire takes up a significant amount of space, and single-gang outlet boxes may not provide enough space when relatively large wire sizes are used.
Single-gang outlet boxes are ideal for many wiring applications and are commonly used in relatively low current 15-20 ampere, service. The wire sizes used in these applications are relatively small and easy to manipulate compared to the wiring used in dryer and range applications. The opening dimensions of standard sized outlet boxes is large enough to accommodate outlet receptacles used in dryer and range applications. However, the outlet box does not provide adequate space to allow for ease of wire installation or for storage due to the large wire sizes required by heavy current load applications. While increasing the depth of the box provides more storage for the wires, it increases the difficulty of pulling the wires into the box as the wire openings are typically in the bottom of the box or in a side wall close to the bottom. In addition, in certain applications the depth of the box must be kept to a minimum due to space constraints.
The problems associated with large wire sizes has been addressed in the prior art by using an outlet box that is larger than a single-gang box. A larger outlet box provides both the room for an installer to manipulate the wiring in order to pull the wire into the box, as well as providing space for the wire and the receptacle to be stored once the receptacle is installed.
Large outlet boxes include such outlet boxes as the 4" square and the double and triple-gang boxes. The 4" square box is typically surfaced mounted and includes a cover plate that covers the entire box. The cover includes cutouts that provide an opening for the outlet so the appliance may be plugged into the receptacle. Surface mounted boxes present several disadvantages such as taking up wall space and being aesthetically unappealing. Additionally, if a single receptacle is to be used with a 4" box a separated reducing component must be used to provide a mounting surface for the receptacle. The use of an extra component increases both the cost and time associated with the installation.
The double-gang box is typically formed from joining two single-gang boxes side to side, and therefore, has approximately twice the width as the single-gang outlet box. As previously stated, these boxes typically are used when two receptacles or switches are to be installed. While such outlet boxes are typically in-wall mounted, they still present the problem of not being aesthetically appealing since they require two cover plates in order to cover the entire box. In dryer and range applications, typically only one outlet is installed per box, therefore, in order to effectively cover the entire outlet box one cover plate is used to cover the receptacle and a second cover plate is needed to cover the remainder of the box opening. If a standard size single-gang outlet box had been employed, only one cover plate would be necessary, thereby reducing costs and presenting a more aesthetically appealing appearance.
It would, therefore, be desirable to have an outlet box which may be in-wall mounted, have an opening of a standard size single-gang outlet box, while still providing access to the interior of the outlet box in order to facilitate the introduction of wires into the box and provide space for the installation of the receptacle.